Our patient was treated with anticoagulants for more than 3 weeks with no resolution of her thrombi, so finally decision was to go for surgical thrombectomy. Intraoperatively, thrombi were quite adherent to the atrial wall as well as the pulmonary arteries supporting the evidence of a clear in situ evolution of such thrombi intracardially for a long period of time, which made it persist despite anticoagulation.